Color contrast enhancing sunglass lens

Abstract

A color contrast enhancing sunglass lens includes a lens body and a multi-layer coating disposed on the lens body. The multi-layer coating includes a set of alternating layers formed of materials having different refractive indices and confines the transmission of visible light to a predetermined spectral profile having at least three high transmission bands that include blue, green and red bands and that have a maximum of spectral transmittance no less than 60%, three low transmission bands that include purple, cyan and yellow bands and that have a minimum of spectral transmittance no greater than 40%, and no spectral transmittance being less than 15% between 475 and 650 nm. The color contrast enhancing sunglass lens as disclosed meets the ANSI specification Z80.3-2009 section 4.6.3.3.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to Taiwanese application no. 101113233, filed on Apr. 13, 2012, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to a sunglass lens, more particularly to a color contrast enhancing sunglass lens comprising a lens body and a multi-layer coating.[0004]2. Description of the Related Art[0005]Besides conventional functions for attenuation of light and UV protection, along with the increasing demand for color contrast enhancement, the use of color contrast enhancing lenses has become increasingly popular in sunglasses. As used herein, the phrase “color contrast” refers to the difference in color that makes an object distinguishable. The image of an object can be enhanced by increasing the difference in light transmission between primary color bands (i.e., the blue band having a wavelength ranging from...

AI Technical Summary

Benefits of technology

[0010]Therefore, the object of the present invention is to provide a color contrast enhancing sunglass lens that can alleviate at least one of the aforesaid drawbacks of the prior art.

Problems solved by technology

However, the Larson lens system shows no low transmission band in the cyan band centered at about 500 nm for enhancing the contrast of blue and green to cyan.

However, some serious problems prohibit the filter of Johnson Jr. from being a useful sunglass lens.

First, the filter blocks the transmittance of light at 490 nm and 590 nm, and thus, it fails to meet the ANSI specification Z80.3-2009 section 4.6.3.3 for traffic signal recognition, which requires the spectral transmittance of a tinted lens to be not less than 20% of the lens luminous transmittance between 475 nm and 650 nm.

Moreover, when used under bright sunlight condition, the filter made from the transparent substrate and the multi-layer coating produces unpleasant reflection to incident light from behind the wearer or the wearer' s face.

Furthermore, the filter allows relatively high transmission of orange light at 610 nm and 620 nm, and thus is not good for enhancing the contrast of red from orange.

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